Shopping for a new air conditioning system or furnace can be stressful. If you want to find the best HVAC system for your home, it's natural to look for models with the highest efficiency ratings.
Surely the most efficient equipment will provide the most comfort and lowest energy bills, right?
It’s not quite that simple.
Energy efficiency isn't the only thing that matters when it comes to new air conditioner installation or replacing your furnace. While many homeowners focus only on efficiency ratings, proper HVAC system sizing is often even more important for your home's comfort and your utility bills.
Proper sizing also influences humidity control and long-term reliability. The best HVAC system for your home delivers energy efficiency and proper sizing.
In this blog, we'll explain what an air conditioner's SEER rating or SEER2 rating actually measures, why proper HVAC system sizing is so important and why experienced HVAC professionals consider both when recommending the best HVAC system for your home.
High Seer Ratings: What Do They Mean?
A SEER rating, (Seasonal Energy Efficiency Ratio), shows how effectively an AC cools your home over a standard cooling season. A SEER2 rating is the newer version of SEER, using test procedures that better reflect real-world operating conditions. Today’s new air conditioners have a SEER2 designation, simply because this is the current rating system for cooling equipment.
Fuel-burning heating system efficiency is rated by something called AFUE, which is short for Annual Fuel Utilization Efficiency. Like SEER and SEER2 ratings, higher AFUE ratings indicate a high-efficiency HVAC system that uses less electricity to achieve indoor comfort than lower-rated systems under standardized laboratory testing.
However, high numbers don't automatically guarantee lower utility bills. Real-world heating and air conditioner efficiency depends on more than just efficiency ratings, including the quality of the installation, the state of your ductwork, your home's insulation, thermostat settings and, most importantly, HVAC system sizing. Even the highest-rated system cannot operate at its best if it is too large or undersized for the home.
Why Correct HVAC System Sizing Matters More Than Most Homeowners Realize
Many assume a bigger air conditioner or furnace will make their home the most comfortable or that they should just replace their old HVAC system with a unit of the same capacity. The truth is, new heating system installation or a new air conditioner should be chosen based on your home's actual heating and cooling needs—not just square footage or the capacity of the old system.
That's why reputable contractors perform an HVAC load calculation, also called a Manual J calculation, before selecting replacement equipment. A Manual J calculation analyzes many variables that affect your home's heating and cooling requirements, including:
- Home square footage
- Ceiling height
- Window size and placement
- Home insultation levels
- Drafts and air leakage
- Area climate
- Household occupants
- Heat produced from appliances and lighting
- Air duct condition
A properly sized air conditioner runs for enough time to cool your home more uniformly while removing excess humidity. That means more even temperatures, better indoor comfort and improved indoor humidity management. It also helps the equipment to run more effciently, reducing excessive wear and tear that can shorten its lifespan or lead to frequent or expensive repairs.
When your heating or cooling system is correctly sized, you get improved comfort and more dependable performance.
Problems Caused by Oversized and Undersized Systems
Many homeowners are tempted to buy the most energy efficient, largest-capacity air conditioner or heating system on the market. The truth is, that’s rarely a great idea.
heating and cooling systems that are bigger than your home needs or too small can create indoor comfort challenges, increase operating costs and reduce efficiency regardless of their SEER rating.
Drawbacks of Oversized HVAC Systems
An oversized air conditioner or heating system may work quickly, but that doesn't mean it performs efficiently.
- Short cycling: An oversized HVAC system turns on and off frequently, reducing efficiency and increasing wear.
- Humidity problems: Oversized air conditioners reach the set temperature too fast to remove excess moisture from the air.
- Hot and cold spots: Some rooms get too cold while others never feel comfortable.
- Additional equipment wear: Even though the system reaches the target temperature rapidly, those repeated on-and-off cycles can cause avoidable breakdowns due to the strain.
Cons Associated with Undersized HVAC Systems
An undersized HVAC system can have the opposite problem:
- Long run times: The system stays on for extended periods trying to reach the desired temperature, which also causes unnecessary wear and tear.
- Difficulty maintaining the desired temperature: Your home may not feel comfortable during hot weather or always feel chilly in the winter.
- Greater energy usage: Running for extended periods can increase energy costs.
- Extra stress during severe weather: HVAC systems that are too small can struggle in extreme temperatures, increasing equipment wear and the chance of failure.
Finding the Right Balance Between Efficiency and Size
When weighing the pros and cons of a high SEER vs right-sized system, don't forget that you don't always need the highest-efficiency model on the market.
More often than not, a professionally sized, mid-efficiency heating and cooling system will outperform an overly large premium system because it operates the way it was designed to.
Theideal choice is an energy-efficient HVAC system that's properly sized for your home, your budget, your climate and your long-term goals.
When deciding how to choose a new air conditioner or furnace, consider:
- Energy savings: Higher-efficiency and right-sized systems can reduce electricity use.
- Upfront investment: High-efficiency AC and heating systems often cost more initially than mid-range models but can lower long-term energy costs.
- Electricity rates: Areas with higher electricity rates may see greater long-term savings from higher-efficiency units.
- Climate: It's essential your heating or cooling system has the right capacity to handle areas with very cold winters or very hot summers.
- How long you'll own the home: If you plan to stay in your home for many years, the long-term energy savings of a higher-efficiency unit may be worth the investment.
- Financial incentives: Manufacturer promotions, {utility|equipment rebates and tax credits can reduce the overall cost of higher-efficiency systems.
Real-World Situation: High Seer vs. Right System Size
What does this look like in a real world scenario?
Suppose there are two neighboring homes.
In the first, the homeowner chooses a premium high-efficiency HVAC system that's too big for the house because the contractor simply matched the previous unit. Next door, the second homeowner installs a properly sized, mid-SEER or AFUE system after completing a Manual J calculation.
Even though the second system has a lesser efficiency rating on paper, it may deliver lower operating costs, better home comfort, improved humidity control and have a longer lifespan because it's properly matched to the home's needs.
Choose the Local HVAC Professional Who Designs the Right Solution
Replacing your HVAC system should involve more than selecting the unit with the highest efficiency rating. An ideal system is one that meets your home’s heating and cooling requirements.
At Smyth Air Conditioning, our experienced professionals perform an HVAC load calculation. Our team will evaluate your home's layout and construction, your household's comfort needs and recommend equipment that's designed specifically for your home—not simply the highest-capacity, most expensive unit or the one with the highest AFUE or SEER2 rating.
Our heating and cooling specialists will connect you with any available rebates or tax incentives and provide information about HVAC financing options that make high-efficiency systems more accessible for all budgets.
Schedule an HVAC consultation online with Smyth Air Conditioning to get started. We'll evaluate your home, answer any questions and help you choose the correctly sized high-efficiency system that keeps your family comfortable for years to come.